Quick disconnect couplings are often used in applications where it is necessary to connect and disconnect fluid lines with some regularity. In some applications, the quick disconnect coupling is provided with a valve structure in an insert and a valve structure in a receiving coupling body that allows fluid to flow through the coupling when in a connected state, but prevents flow through either line when in a disconnected state. Often, these types of couplings have spring-biased valves which make it necessary to lock the coupling together with a locking mechanism such that the valves and/or line pressure do not force the insert and coupling body apart undesirably. Such locking mechanisms can be manufactured from a metal, while the insert and coupling bodies are manufactured from a plastic. In such an arrangement, the insert is often subjected to eccentric side loading and point stress from the locking mechanism, which can limit performance of the coupling.